The present invention relates to a method of controlling information in a multimedia system handling various kinds of information.
Recently, there have been broadly developed multimedia systems employing computers handling various kinds of information (to be referred to as media information herebelow) related to various kinds of expressions and representations of such items as a character string, a graphic image, a video image, a moving picture, a music piece, and a voice so as to display these information items on a screen of a display and/or to reproduce such information items in cooperation with a screen image. A multimedia system is disclosed in for example JP-A-62-47737. There exists, for example, a multimedia system in which screen structures (to be referred to as screen layouts herebelow) of a display and switching conditions (to be referred to as transition conditions herebelow) of screen information are beforehand defined so that at an occurrence of an event (for example, a command input from a user) while a screen layout is being displayed on a display, a screen change-over takes place to another screen layout according to a transition condition thus defined in advance. This system is in general called a hyper-media system.
In the hyper-media system, when defining screen layouts, the user may possibly desire to use an identical element (to be referred to a media information element herebelow) of media information in a plurality of screen layouts and/or to modify a portion of a media information element copied from a screen layout before the element is used.
In the former case where an identical element of media information is utilized in a plurality of screen layouts, data related to the media information element need only be stored in a storage of the multi-media system to be shared between the screen layouts.
In this case, however, when the user modifies the media information element on either one of the associated screen layouts, the media information element is modified for all of the related screen layouts.
Moreover, in the latter case where a portion of a media information element transcribed from another screen layout is to be modified, it is only necessary to copy data related to the media information element stored in the storage onto another area thereof so as to use the copied data as the destination screen layout.
However, in this case, when the media information element is copied from the source screen layout onto the destination screen layout, there are used in the storage an amount of storage areas associated with the number of copy operations. Actually, it may occasionally occur that the user does not alter the media information element thus copied. In such a case, the storage area is uselessly consumed for the copy operation.
In addition, also when the media information element is varied after the copy, there are required storage areas in association with the number of copy operations. This implies a problem in the storage capacity of the storage when the media information elements are, for example, bit map data of a large volume of data.